The Ebola viruses, and the genetically-related Marburg virus, are filoviruses associated with outbreaks of highly lethal hemorrhagic fever in humans and primates in North America, Europe, and Africa. Peters, C. J. et al., Filoviridae: Marburg and Ebola Viruses. in Fields Virology. (eds., Fields, B. N., Knipe, D. M.& Howley, P. M.) 1161-1176 (Philadelphia, Lippincott-Raven, 1996); Peters, C. J. et al, Semin. Virol 5:147-154 (1994). Ebola viruses are negative-stranded RNA viruses comprised of four subtypes, including those described in the Zaire, Sudan, Reston, and Ivory Coast episodes. Sanchez, A. et al., PNAS (USA) 93:3602-3607 (1996). Although several subtypes have been defined, the genetic organization of these viruses is similar, each containing seven linearly arrayed genes. Among the viral proteins, the envelope glycoprotein exists in two alternative forms, a 50-70 kilodalton (kDa) secreted protein of unknown function encoded by the viral genome and a 130 kDa transmembrane glycoprotein generated by RNA editing that mediates viral entry. Peters, C. J. et al., Filoviridae: Marburg and Ebola Viruses. in Fields Virology. (eds., Fields, B. N., Knipe, D. M.& Howley, P. M.) 1161-1176 (Philadelphia, Lippincott-Raven, 1996); Sanchez, A. et al., PNAS (USA) 93:3602-3607 (1996). Other structural gene products include the nucleoprotein (NP), matrix proteins VP24 and VP40, presumed nonstructural proteins VP30 and VP35, and the viral polymerase (reviewed in Peters, C. J. et al., Filoviridae: Marburg and Ebola Viruses. in Fields Virology. (eds., Fields, B. N., Knipe, D. M.& Howley, P. M.) 1161-1176 (Philadelphia, Lippincott-Raven, 1996)). Although spontaneous variation of its RNA sequence does occur in nature, there appears to be less nucleotide polymorphism within Ebola subtypes than among other RNA viruses (Sanchez, A. et al., PNAS (USA) 93:3602-3607 (1996)), suggesting that immunization may be useful in protecting against this disease. Previous attempts to elicit protective immune responses against Ebola virus using traditional active and passive immunization approaches have, however, not succeeded. Peters, C. J. et al., Filoviridae: Marburg and Ebola Viruses. in Fields Virology. (eds., Fields, B. N., Knipe, D. M.& Howley, P. M.) 1161-1176 (Philadelphia, Lippincott-Raven, 1996); Clegg, J. C. S. et al., New Generation Vaccines. (eds., Levine, M. M., Woodrow, G. C., Kaper, J. B.& Cobon, G. S.) 749-765 (New York, N.Y., Marcel Dekker, Inc. 1997); Jahrling, P. B. et al., Arch. Virol. Suppl. 11:135-140 (1996).
It would thus be desirable to provide a vaccine to protect against disease caused by infection with Ebola virus. It would further be desirable to provide methods of making and using said vaccine.